Graphene is a two-dimensional (2D) sheet structure of sp2-bonded carbon atoms with unique electronic, chemical and mechanical properties. The significance of these unique properties is now just being realised, with graphene or graphene-based sheets being applied in various applications such as energy storage, catalysis, sensing and composites. In many of these applications to date it has been the 2D form of the graphene-based sheets that has been exploited.
To further realise the potential of graphene-based materials, a considerable amount of research has been directed toward forming three-dimensional (3D) graphene-based structures. One particular field of research showing great promise is the development of graphene-based foam structures.
A number of techniques have been developed for producing graphene-based foams. For example, 3D graphene-based porous materials have been prepared by self-gelation during the reduction of graphene oxide or through chemical vapour deposition (CVD) on porous metal templates. Despite providing for 3D graphene-based materials, such foams have generally been reported as having relatively poor mechanical properties such as being brittle and having low mechanical flexibility. Furthermore, the foams typically shrink during manufacture making the resulting dimensions of the foam difficult to control.
To address at least some of these problems, polymer/graphene composite foam structures have been developed. While incorporating polymer into the foam structure can impart improved mechanical properties such as compressibility, the advantageous properties of the graphene-based material per se can be inherently diminished.
Accordingly, there remains an opportunity to develop graphene-based foams that exhibit improved mechanical properties while at the same time minimising the loss of unique properties attributed to the graphene-based material per se.